Exponential nitrogen(N) loading approach has been used to optimize seedling growth in container seedling production. However, the response of seedling growth to N loading and optimal N loading rates are species-depend...Exponential nitrogen(N) loading approach has been used to optimize seedling growth in container seedling production. However, the response of seedling growth to N loading and optimal N loading rates are species-dependent. There is a lack of information on optimal N loading in container production of Australian Blackwood(Acacia melanoxylon) seedlings. In this study, 7 exponential N loading at rates of 0, 50, 100, 200, 300, 400, and 600 mg N seedling-1, respectively, were applied at the week 3, 6, 9, 12 and 14 after transplanting to determine optimal loading approach based on seedling height, root collar diameter(RCD), biomass accumulation and N uptake in tissue-cultured Australian Blackwood(A. melanoxylon) seedlings. Seedlings did not respond to N loading 3 wk after transplanting, then the accumulative addition of N loading for improved RCD and seedling height was 12.99 and 28.02 mg N seedlings-1 in the 100 N and 400 N treatment 6 wk after transplanting, respectively, and on 9 and 12 wk, that for improved seedling growth was 63.64 and 400 mg N seedling-1 in the 200 N and 400 N treatment, respectively. Vector diagnosis of final biomass and N status indicated that the dose of 100 and 400 mg N seedling-1 was characterized to be "deficient" and "optimum" dose of exponential N loading for Blackwood seedlings. These conclusions promise to figure out a precise fertilization regime for Blackwood seedlings and the demonstration of dynamic seedling performance could be used for other tree species.展开更多
基金funded by Complement Public Benefit Research Foundation of state forestry administration,P.R.China
文摘Exponential nitrogen(N) loading approach has been used to optimize seedling growth in container seedling production. However, the response of seedling growth to N loading and optimal N loading rates are species-dependent. There is a lack of information on optimal N loading in container production of Australian Blackwood(Acacia melanoxylon) seedlings. In this study, 7 exponential N loading at rates of 0, 50, 100, 200, 300, 400, and 600 mg N seedling-1, respectively, were applied at the week 3, 6, 9, 12 and 14 after transplanting to determine optimal loading approach based on seedling height, root collar diameter(RCD), biomass accumulation and N uptake in tissue-cultured Australian Blackwood(A. melanoxylon) seedlings. Seedlings did not respond to N loading 3 wk after transplanting, then the accumulative addition of N loading for improved RCD and seedling height was 12.99 and 28.02 mg N seedlings-1 in the 100 N and 400 N treatment 6 wk after transplanting, respectively, and on 9 and 12 wk, that for improved seedling growth was 63.64 and 400 mg N seedling-1 in the 200 N and 400 N treatment, respectively. Vector diagnosis of final biomass and N status indicated that the dose of 100 and 400 mg N seedling-1 was characterized to be "deficient" and "optimum" dose of exponential N loading for Blackwood seedlings. These conclusions promise to figure out a precise fertilization regime for Blackwood seedlings and the demonstration of dynamic seedling performance could be used for other tree species.
